This application note describes how to set and monitor a determined liquid flow rate and perform a flow control for your microfluidic experiments by using an Elveflow® pressure & flow control instrument and a flow sensor. The new version of the Elveflow® smart software allows to virtually turn your pressure controller into a syringe pump keeping the advantages of both methods (high performance, ease of use, intuitiveness, etc.)

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Setup diagram

This picture shows the microfluidic setup that will be used for this application note.

setup microfluidic valve switch

The Elveflow® pressure control instrument used in this note is the OB1 MkII pressure controller, but we could just as easily have used an AF1 Premium pressure generator for this task.

As often as possible avoid using soft tubing (like Tygon) which involves compliance and then increases the response time of the system. If you’re not familiar with microfluidic tubings, you may read our dedicated tutorials.

The following diagram illustrates the complete chain of elements involved in this application note. You will need to assemble all those parts to set up your experiment.

Microfluidic flow control Diagram V2


Using the Elveflow® smart interface to monitor a determined liquid mass flow rate. Be sure that all the cables and tubing are well connected to your Elveflow® (USB cable, 24V DC, Flow sensor data cable, etc). Perform leakage tests and remove any air bubbles before starting your experiment to ensure a good flow rate regulation. Knowing what fitting is best suited for your needs is a first step towards success. If you’re not familiar with microfluidic fittings, you may read our specific tutorials. The flow sensor is very sensitive to vibrations and movement perturbations so it is recommended to fix it to a stable surface as often as possible.

In order to monitor a constant flow rate of e.g. 50µL/min on the Elveflow® smart interface for your microfluidic system, it is necessary to follow the next steps:

  • Step 1 - Open the Elveflow® Smart Interface in the computer and select the instrument which is going to be used (OB1mix01 in the example case).
  • Step 2 - Click on the “flow sensor” button and select the sensor range that it is going to be used on the corresponding channel. (50µL/min on channel 1 in the example case).
  • Step 3 - Choose the reservoir size (Eppendorf 1,5 mL in the example case) and the sample amount (also 1,5 mL in the example case).
  • Step 4 - Back on the main window, activate the flow button on the pertinent channel (channel 1 in the example case) and set a flow rate value in µL/min (30µL/min in the example case). Please, note that at the beginning, the reservoir’s color is red but at the moment the flow rate is stable it becomes blue.
  • Step 5 (optional) - If needed, it is possible to see a graph display by clicking on the “open graph display” button. Set the desired maximum and minimum shown parameters on the display window for pressure and flow rate and press the play icon to launch the pressure and flow rate profiles display. Select the channels you want to display by ticking the corresponding boxes on the channel display selection block.

The screenshots corresponding to these steps are in the following gallery:

Congratulations! You’ve achieved the flow rate control using  an Elveflow® Flow sensor and the Elveflow® pressure control instrument!


We  provide the only microfluidic flow control system using Piezo technology that enables a blazing fast flow change in your microdevice.

Piezo electric microfluidics flow control